The present invention relates to a system for attaching a vehicle wheel to a wheel hub with a plurality of nuts secured on lug bolts. More particularly, the invention relates to such a system where one of the nuts is a lock nut, having a wrench engaging surface that cannot be rotated by standard wrenches utilized to tighten or remove polygonal nuts.
Lock nuts are used to secure expensive wheels, such as aluminum alloy wheels, and prevent theft. A lock nut typically has a generally cylindrical outer periphery with a plurality of radially inwardly extending grooves. A tool having ribs that extend into the grooves is required to remove the lock nut. The width, length and circumferential position of the lock nut grooves defines a pattern that is varied periodically, such that a single lock nut tool cannot be utilized to remove all lock nuts. If a number of patterns are utilized, and varied periodically, a thief is prevented from easily removing the lock nut and the expensive wheel. As an example, if a total of ten different lock nut patterns are typically used, a thief would be required to have ten corresponding lock nut removing tools. The thief could not quickly remove the wheel, as there would be some time required to match the particular lock nut with a particular lock nut removing tool.
In a typical application, a single lock nut is utilized, with the remainder of the lug bolts receiving standard hexagonal nuts. The prior art lock nut tools will not rotate hexagonal nuts. With the prior art system, an owner of a vehicle must have a first tool to rotate the hexagonal nuts, and a second tool to rotate the lock nut.
The requirement of separate tools for the lock nut and the hexagonal nuts restricts the use of lock nuts in vehicle manufacturing plants. Vehicle manufacturing plants wish to simplify production, and eliminate as many distinct type of tools, or workstations, as possible. In assembling a vehicle wheel to the wheel hub with a prior art system that utilizes a single lock nut, a manufacturer must have two types of tools, and must maintain a dedicated assembly station equipped with the lock nut tool.
It is an object of the present invention to disclose a vehicle wheel mounting system in which a single tool may be utilized to tighten both a lock nut and the hexagonal nuts upon the lug bolts.